Hello,
i want to implement the MUSIC algorithm for frequency estimation in pd.
Therefore i have to calculate eigenvalues and eigenvectors of a certain matrix. The GNU scientific library is a collection of routines for numerical computing and provides functions for calculating eigenvectors and -values.

My problem is that i don't have any idea how to compile my external using the gcc.
Compiling a simple C programm (not as pd-external) requires the command:
> gcc -Wall -c example.c
After that i get a C object file named example.o. Now i have to link this object file with the gsl library like this:
> gcc example.o -lgsl -lgslcblas -lm
Afterwards i get the binary which i can execute with ./example

The question:
Which commands do i have to use to compile a pd-external using the gsl?

Please excuse me for my bad english.
Hope someone could help me.
Best regards,
Joul

P.S.
I already know the usual compiling instructions for pd-externals like:
> gcc -c helloworld.c -o helloworld.o
> ld -export_dynamic -shared -o helloworld.pd_linux helloworld.o -lc -lm

Hi Joul,

unfortunately is not just a matter of providing the correct compilation command.
Basically in your C program you need to define the data interface to PD data types,
and the method associated with them. I suggest you to first reading the introduction
on how to make an external for PD:

http://iem.at/pd/externals-HOWTO/

which is the required starting point. Your project sounds interesting, so keep us
informed..

Cheers,

AlbertoZ

Hi AlbertoZ,
thank You for Your answer. But i'm already familiar with the HowTo from johannes m zmölnig. I've also written my first externals providing some fractional delay functions yet. And they work...

I've attached a short example calculating the eigenvalues of a 2x2 matrix which is the estimated covariance matrix from 2 input signals. Besides the source code already uses the GNU Scientific Library. Compiling with
> gcc -c music~.c -o music~.o
returns no errors. Therefore i think i've done no misstakes so far.

My problem is now how to go on with linking etc. Or better say how to combine the two linking commands from my first post to get a cool external...

For sure there are some optimizations in the source code. Please let me know if i did some unusual programming in the example.

I hope You can help me.

Best regards, Joul

http://www.pdpatchrepo.info/hurleur/music~.c

Hi Joul,

> thank You for Your answer. But i'm already familiar with the HowTo from johannes m zmölnig. ..

sorry, it wasn't clear from the first post.
What's the result of the link command as it is now (i.e. like > ld -export_dynamic -shared -o helloworld.pd_linux helloworld.o -lc -lm)?
Post also the .h files (gsl_eigen.h etc.), I'll try to look at it...

cheers,

AlbertoZ

Hi AlbertoZ,

sorry, it wasn't clear from the first post.

No problem, it was my fault.

I found out how it works! It's quiet simple, i only have to change the linking command into:
> ld -export-dynamic -shared -o music~.pd_linux music.o -lc -lm -lgsl -lgslcblas

And it works..! (Sometimes I'm such a fool) but now happy like a little child!
Think of the huge possibilities for signal processing which i can use now by including the GNU Scientific Library... pd is great!

Thank You for Your quick replies! I will post my external when i've finished...

Best regards, Joul

Hello again,
now I've finished a first trial of the mentioned external.
Unfortunately I get an error message on the pd shell when loading the external:
"warning: signal method overrides class_mainsignalin"

Could somebody tell me what this means? For further information I've attatched my source code.

Thanks in advance!

Best regards, Joul

http://www.pdpatchrepo.info/hurleur/music~.c